I've been shifting mine at 8k for years, never a problem, It's beefed up a little with some Fairbanks goodies, but for the weight difference and the ability to stay together, a 904 is plenty tough enough for a 360. My 340 is taken about as far as I can go without juice or a blower, and it's taken all I could give it.
Offy intake, 636 Lunatti solid, 207 intakes, 180 exhausts, Intake and heads matched ported to about a hair between ports, 850 dominator, 4k stall, MSD, Accel dis.